特殊形状贯穿件焊接残余应力和疲劳分析
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摘要
由于焊接过程中高度集中的瞬时热输入,焊件内部将产生相当大的残余应力和残余变形。而焊接残余应力会严重影响结构的使用性能和可靠性,因此,对焊接残余应力和疲劳寿命进行计算和分析具有很重要的工程意义。
本文首先对焊接过程中的温度场和应力场的基本理论进行了阐述。然后采用Ansys软件的热—结构耦合功能,利用间接耦合法,对特殊形状贯穿件多道焊焊接过程的温度场和应力场做了数值仿真。最后,结合疲劳分析软件FE-SAFE,以焊接残余应力场为基础,针对不同种类动载荷的作用,对焊接件进行了疲劳寿命和指定循环次数下的安全系数的模拟。
在有限元仿真过程中,考虑了材料热物理性能和力学性能随温度的变化,通过APDL编写程序实现了双椭球热源模型的移动加载,同时利用“生死单元”技术实现了多道焊焊缝填充的动态过程,并给出了焊接温度场的动态变化云图和焊接残余应力的分布云图。
从贯穿件整个模型及二分之一模型的瞬态温度场和应力场的模拟结果可以看出,用二分之一模型代替整个模型,不仅大大减少计算时间,而且可以保证计算精度；对比研究两面交替焊和一面焊两种焊接方式时的焊接件残余应力场模拟结果表明,两面交替焊不仅降低了温度场的最高温度,也大大减小了焊接残余应力。疲劳分析结果表明,焊趾位置是疲劳寿命最小值出现的地方,焊缝及其附近区域为不安全的区域位置。
Because of high centralized instantaneous heat input in the process of the welding, a great deal of residual stresses and deformations should be brought in the welding structure, which can heavily influence the capability and reliability of the structure. Therefore it is essential to calculate and analyze the residual stress and the fatigue lifetime of the welding structure.
The basic theories of the temperature field and the residual stress field are first described in the paper. Then the temperature field and residual stress field for the multi-pass welding of special penetration assembly are simulated with the thermal-structure coupling function and indirect coupling method of software ANSYS. Finally based on the residual welding stress field, the fatigue lifetime and the factor of safety under certain cycle times of the welding structure under different load paths are analyzed by the fatigue analysis software FE-SAFE.
In the process of numerical simulated calculating, it takes into account that the material property parameters are different with temperature changes and the double ellipsoid heat source model is chosen to express the heat input. Using ANSYS APDL language to compile programs to apply moving heat source load, the process of pass filling dynamical welding by using "Element Birth and Death" is realized. Then dynamic pictures of welding temperature field and tendency of residual welding stresses distribution are shown by post-solution.
Comparing temperature field and stress field distribution of the whole model with that of the half model, the half model is a reasonable simplification instead of the whole model. Analyzing the residual stress of the alternative welding sequence and the one-side welding sequence, the results show that alternative welding sequence can obviously reduce the highest temperature and the residual stresses, so it is superior to one-side welding. The results coming from the FE-SAFE show that the minimum fatigue lifetime occurs in the weld toe; the weld bead and the surrounding region are dangerous regional positions for fatigue lifetime.
本文首先对焊接过程中的温度场和应力场的基本理论进行了阐述。然后采用Ansys软件的热—结构耦合功能,利用间接耦合法,对特殊形状贯穿件多道焊焊接过程的温度场和应力场做了数值仿真。最后,结合疲劳分析软件FE-SAFE,以焊接残余应力场为基础,针对不同种类动载荷的作用,对焊接件进行了疲劳寿命和指定循环次数下的安全系数的模拟。
在有限元仿真过程中,考虑了材料热物理性能和力学性能随温度的变化,通过APDL编写程序实现了双椭球热源模型的移动加载,同时利用“生死单元”技术实现了多道焊焊缝填充的动态过程,并给出了焊接温度场的动态变化云图和焊接残余应力的分布云图。
从贯穿件整个模型及二分之一模型的瞬态温度场和应力场的模拟结果可以看出,用二分之一模型代替整个模型,不仅大大减少计算时间,而且可以保证计算精度；对比研究两面交替焊和一面焊两种焊接方式时的焊接件残余应力场模拟结果表明,两面交替焊不仅降低了温度场的最高温度,也大大减小了焊接残余应力。疲劳分析结果表明,焊趾位置是疲劳寿命最小值出现的地方,焊缝及其附近区域为不安全的区域位置。
Because of high centralized instantaneous heat input in the process of the welding, a great deal of residual stresses and deformations should be brought in the welding structure, which can heavily influence the capability and reliability of the structure. Therefore it is essential to calculate and analyze the residual stress and the fatigue lifetime of the welding structure.
The basic theories of the temperature field and the residual stress field are first described in the paper. Then the temperature field and residual stress field for the multi-pass welding of special penetration assembly are simulated with the thermal-structure coupling function and indirect coupling method of software ANSYS. Finally based on the residual welding stress field, the fatigue lifetime and the factor of safety under certain cycle times of the welding structure under different load paths are analyzed by the fatigue analysis software FE-SAFE.
In the process of numerical simulated calculating, it takes into account that the material property parameters are different with temperature changes and the double ellipsoid heat source model is chosen to express the heat input. Using ANSYS APDL language to compile programs to apply moving heat source load, the process of pass filling dynamical welding by using "Element Birth and Death" is realized. Then dynamic pictures of welding temperature field and tendency of residual welding stresses distribution are shown by post-solution.
Comparing temperature field and stress field distribution of the whole model with that of the half model, the half model is a reasonable simplification instead of the whole model. Analyzing the residual stress of the alternative welding sequence and the one-side welding sequence, the results show that alternative welding sequence can obviously reduce the highest temperature and the residual stresses, so it is superior to one-side welding. The results coming from the FE-SAFE show that the minimum fatigue lifetime occurs in the weld toe; the weld bead and the surrounding region are dangerous regional positions for fatigue lifetime.
引文
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[2]田锡唐主编.焊接结构.北京：机械工业出版社,1996：10页
[3]张文钺.焊接传热学.机械工业出版社,1989：11-31页
[4]陈楚等.数值分析在焊接中的应用.上海交通大学出版社,1985：15-16页
[5]Yueda. Analysis of thermal elastic-plastic stress and strain during welding. Trans.Japan Welding Soc,1971:90-94P
[6]Vaidyanathan. Residual stresses due to circumferential welds. ASME Journal of Engineering Materials and Technology,1973:233-239P
[7]Erybicki. Computation of residual stresses due to multi-pass welds in pipeing systems. Journal of Pressure Vessel Technology,1979:149-153P
[8]B. Brickstad, B.L. Josefson. A parametric study of residual stress in multi-pass butt-welded stainless steel pipes. International Journal of Pressure Vessels and Piping,1998(75):11-25P
[9]Ydong, Jkhong, Cltsal, et al. Finite element modeling of residual stresses in austenitic stainless stell pipe girth welds. Welding Jouranl,1997:442P
[10]Lelindgren, Lkarlsson. Deformation and stresses in welding of shell structures. International Journal for Numerical Methods in Engineering, 1998:635-638P
[11]Dean Deng, Hidekazu Murakawa. Numerical simulation of temperature field and residual stress in multi-pass welds in stainless steel pipe and comparison with experiment measurements. Computational Materials Science,2006(37):269-277P
[12]Dean Deng, Hidekazu Murakawa, Wei Liang. Numerical and experimental investigation on welding residual stress in multi-pass butt-welded austenitic stainless steel pipe. Computational Materials Science,2007:1-11P
[13]Dean Deng, Hidekazu Murakawa. Prediction of welding residual stress in multi-pass butt-welded modified 9Cr-1Mo steel pipe considering phase transformation effects. Computational Materials Science 2006(37): 209-219P
[14]汪建华,陆皓.焊接残余应力形成机制与消除原理若干问题的讨论.焊接学报,2002,23(3)：75-79页
[15]陈楚,汪建华,杨洪庆.非线性焊接热传导的有限元分析和计算.焊接学报,1983,3：139-148页
[16]汪建华,戚新海,钟小敏.焊接结构三维热变形的有限元模拟.上海交通大学学报,1994,28(6)：59-65页
[17]魏艳红.不锈钢焊接凝固裂纹应力应变场数值模拟.焊接学报,2000,21(2)：2页
[18]姬书得.水轮机转轮焊接残余应力调控措施的虚拟优化.哈尔滨工业大学博士学位论文,2006：21-89页
[19]赵海燕.分段移动的焊接热源模型的研究与应用.第十次全国焊接会议论文集第二册,2001：1-2页
[20]张建强.焊接应力与变形的数值模拟方法及应用.第十次全国焊接会议论文集第二册,2001：2页
[21]鹿安理.焊接过程仿真领域的若干关键问题及其初步研究.中国机械工程,2002,11(1)：3页
[22]蔡志鹏.大型结构焊接变形数值模拟的研究与应用.清华大学博士学位论文,2001：13-68页
[23]X.B.Lin, R.A.Smith. Finite element modeling of fatigue crack growth of surface cracked plates:Part I:The numerical technique. Engineering Fracture Mechanics,1999(63):503-522P
[24]X.B.Lin, R.A.Smith. Finite element modeling of fatigue crack growth of surface cracked plates:Part Ⅱ:Crack shape change. Engineering Fracture Mechanics,1999(63):523-540P
[25]X.B.Lin, R.A.Smith. Finite element modeling of fatigue crack growth of surface cracked plates:Part Ⅲ:Stress intensity factor and fatigue crack growth life. Engineering Fracture Mechanics,1999,63:541-556P
[26]X.B.Lin, R.A.Smith. Fatigue shape analysis for corner cracks at fastener holes. Engineering Fracture Mechanics,1996
[27]Z.X.Li, T.H.T.Chan, J.M.Ko. Fatigue analysis and life prediction of bridges with structural health monitoring data Part Ⅰ:methodology and strategy. International Journal of Fatigue,2001,23(1):45-53P
[28]T.H.T.Chan, Z.X.Li, J.M.Ko. Fatigue analysis and life prediction of bridges with structural health monitoring data Part Ⅱ:application. International Journal of Fatigue 2001,23(1):55-64P
[29]Z.X.Li, T.H.T.Chan, J.M.Ko. Determination of effective stress range and its application on fatigue stress assessment of existing bridges. International Journal of Solids and Structures 2002,39:2401-2417P
[30]Z.X.Li, T.H.T.Chan, J.M.Ko. Fatigue damage model for bridge under traffic loading application made to the Tsing Ma Bridge. Theoretical and Applied Fracture Mechanics 2001,35:81-91P
[31]Z.X.Li, T.H.T.Chan, J.M.Ko. Evaluation of typhoon fatigue damage for the Tsing Ma Bridge. Engineering Structures,2002,24:1035-1047P
[32]M.Taylor, N.Verdonschot, R.Huiskes, P.Ziouspos. A combined finite element method and continuum damage mechanics approach to simulate the invitro fatigue behavior of human cortical bone. Journal of Materials Science:Materials in Medicine,1999(10):841-846P
[33]P.Colombi. Fatigue analysis of cemented hip prosthesis:model definition and damage evolution algorithms. International Journal of Fatigue,2002, 24:895-901P
[34]P.Colombi. Fatigue analysis of cemented hip prosthesis:damage accumulation scenario and sensitivity analysis. International Journal of Fatigue,2002,24:739-746P
[35]王振波.混凝土温度损伤模型研究.河海大学博士学位论文,2001
[36]邓爱民.混凝土损伤行为特性研究.河海大学硕士学位论文,2001
[37]李景湧.有限元法.北京：北京邮电大学出版社,1999
[38]王勖成,邵敏.有限单元法基本原理和数值方法.北京：清华大学出版社,1997
[39]王国强.实用工程数值模拟技术及其在ANSYS上的实践.西北工业大学出版社,2000：1-187页
[40]ANSYS, Inc. ANSYS Elements Reference. Twelfth Edition. SAS IP, Inc. 2001
[41]史清宇.焊接过程三维数值模拟的研究及应用.清华大学博士学位论文,2000：1-18页
[42]John Goldak. A new finite element model for welding heat source. Metallurgual Transactions,1984,15B(2):299-305P
[43]宋天民.焊接残余应力的产生与消除.北京,中国石化出版社,2005：1-2页
[44]薛忠明.焊接温度场与应力场模拟的研究进展.中国机械工程,2002,13(11)：3页
[45]吴言高,李午申,邹宏军.焊接数值模拟技术发展现状.焊接学报.2002,2(2)：90-100页
[46]林燕,董俊慧,刘军.焊接残余应力数值模拟研究技术的现状与发展.焊接技术,2003(6)：2页
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